Brominated or phosphorus-based flame retardants are known to be highly effective and in many cases are the only options for reducing the fire risk of synthetic materials such as rigid or flexible polyurethane foams. However, the growing public and governmental scrutiny of chemicals, and in particular flame retardants, has increased over the years. The goal is towards more sustainable, reactive, polymeric and/or halogen-free new products. Scrutiny greatly diminishes if a flame retardant is reacted into the polymer matrix and cannot be leached-out.
Thus, there is a demand for reactive phosphorus-containing fire retardants for flexible polyurethane, rigid polyurethane and polyisocyanurate foams, possessing such features as high phosphorus content, clear light color and good compatibility with polyether polyols and polyester polyols employed in the polyurethane industry.